scholarly journals 289 PGV-001: a phase 1 trial of a personalized neoantigen peptide vaccine for the treatment of malignancies in the adjuvant setting

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A316-A316
Author(s):  
Thomas Marron ◽  
Julia Kodysh ◽  
Alex Rubinsteyn ◽  
John Finnigan ◽  
Ana Blazquez ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Phase 1 ◽  
Intracellular Cytokine Staining ◽  
Peptide Vaccine ◽  
Mount Sinai Hospital ◽  
Adjuvant Setting

BackgroundThe efficacy of T cell directed immunotherapies relies on adequate priming of T cells to tumor-specific neoantigens, which some studies have augmented with synthetic neoantigen vaccines. This is the first report of a personalized genomic vaccine (PGV-001) in multiple histologies in the adjuvant setting.MethodsTumor and germline RNA and DNA were sequenced, and neoantigen peptides were selected using our OpenVax custom computation pipeline that identifies and ranks mutant sequences by a combination of predicted MHC-I binding affinity and neoantigen abundance within tumor. Up to 10 peptides were synthesized per patient and were administered over the course of 27 weeks in combination with the poly-ICLC. Primary objectives were to determine 1) the safety and tolerability; 2) the feasibility of PGV-001 production and administration; and 3) the immunogenicity of PGV-001. Secondary objectives included immunophenotyping neoantigen-specific T cells in peripheral blood, and characterization of peripheral blood lymphoid, myeloid and humoral responses. We report here for the first time on the primary endpoints.ResultsVaccine was synthesized for 15 patients. A mean of 1619 somatic variants (range 521–5106) were detected. Our pipeline identified a mean of 67.1 neoantigens/patient (range 8–193) and 9.7 peptides/patient were synthesized (range 7–10). 13 patients received PGV-001 (11 patients received all 10 doses and 2 patients received at least 8 doses) while 2 had progressive disease before vaccine initiation. Transient grade 1 injection site reactions were seen in 31% of patients, and one patient experienced grade 1 fever. There were no other significant adverse events. Ex vivo ELISpot analysis of patient blood demonstrated significant induction of T cell responses following receipt of 10 vaccines that were not present after the 6th vaccine, supporting the need for a prolonged dosing schedule. Robust responses were seen in both CD4 and CD8 T cells by intracellular cytokine staining for TNF-a, IFN-a, and IL-2 following in vitro expansion in the presence of vaccine antigens. Additional studies are ongoing to define the most immunogenic antigens.ConclusionsA personalized neoantigen vaccine of synthetic mutant peptides and adjuvant poly-ICLC was successfully synthesized for 15 patients and administered successfully to 87% patients over the course of 27 weeks. The vaccine was well tolerated, and T cell expansion and reactivity to synthetic neoantigens confirms immunogenicity of neoantigens identified with OpenVax.Trial RegistrationNCT02721043Ethics ApprovalThis study was approved by the IRB of The Mount Sinai Hospital in accordance with Federal law. HSM #15-00841.

Peripheral Blood T Cells Generated After Allogeneic Bone Marrow Transplantation: Lower Levels of Bcl-2 Protein and Enhanced Sensitivity to Spontaneous and CD95-Mediated Apoptosis In Vitro. Abrogation of the Apoptotic Phenotype Coincides With the Recovery of Normal Naive/Primed T-Cell Profiles

Blood ◽  
1999 ◽  
Vol 94 (5) ◽  
pp. 1803-1813 ◽  
Author(s):  
Nadia Chafika Hebib ◽  
Olivier Déas ◽  
Matthieu Rouleau ◽  
Antoine Durrbach ◽  
Bernard Charpentier ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Allogeneic Bone Marrow Transplantation ◽  
Allogeneic Bone ◽  
Bax Protein

Abstract T-cell reconstitution after bone marrow transplant (BMT) is characterized, for at least 1 year, by the expansion of populations of T cells with a primed/memory phenotype and by reverse CD4/CD8 proportions. T lymphocytes from 26 BMT patients (mostly adults) were obtained at various times after transplantation (from 45 to ≥730 days) and were tested for susceptibility to spontaneous apoptosis and anti-Fas triggered apoptosis in vitro. Substantial proportions of CD4+ and CD8+ cells generated during the first year after transplantation, but not by day 730, exhibited in these assays decreased mitochondrial membrane potential (▵Ψm) and apoptotic DNA fragmentation. The apoptotic phenotype tended to disappear late in the follow-up period, when substantial absolute numbers of naive (CD45RA+/CD62-L+) T cells had repopulated the peripheral blood compartment of the BMT patients. The rate of spontaneous cell death in vitro was significantly correlated with lower levels of ex vivo Bcl-2 protein, as assessed by cytofluorometry and Western blot analysis. In contrast, the levels of Bax protein remained unchanged, resulting in dysregulated Bcl-2/Bax ratios. Cell death primarily concerned the expanded CD8+/CD45R0+ subpopulation, although CD45R0− subpopulations were also involved, albeit to a lesser extent. These results show that the T-cell regeneration/expansion occurring after BMT is accompanied by decreased levels of Bcl-2 and susceptibility to apoptosis.

419 Pharmacodynamic biomarkers demonstrate T-cell activation in patients treated with the oral PD-L1 inhibitor INCB086550 in a phase 1 clinical trial

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A445-A445
Author(s):  
Sarina Piha-Paul ◽  
Tara Mitchell ◽  
Solmaz Sahebjam ◽  
Janice Mehnert ◽  
Thomas Karasic ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Ex Vivo ◽  
Phase 1 ◽  
Fold Increase ◽  
T Cell Proliferation ◽  
Ifn Γ

BackgroundPharmacological blockade of the PD-1:PD-L1 interaction with monoclonal antibodies (mAbs) has shown durable clinical responses and overall survival benefit in a variety of malignancies.1 2 Importantly, the most meaningful responses have been associated with enhancement of the antitumor effector functions of T cells as evidenced by increased peripheral T-cell proliferation, infiltration of T cells in tumors, together with increased expression of key interferon-γ (IFNγ) pathway genes, including CXCL9, CXCL10, and granzyme B in both biopsy and peripheral blood samples.3 4 To date, available therapies targeting this pathway are mAbs, but the potential advantages of a small molecule, orally administered, direct antagonist of PD-1:PD-L1 binding have led to the development of INCB086550. INCB086550 is being evaluated in a phase 1 study to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics in patients with solid tumors. This preliminary report describes peripheral pharmacodynamic activity.MethodsPeripheral blood was collected at baseline and at multiple time points posttreatment from 16 patients treated with INCB086550 QD (100, 200 mg) or BID (200, 400 mg). Pharmacodynamic assessments included binding of drug to PD-L1 and secretion of cytokines, IL-2 and IFN-γ with ex vivo restimulation. Measurement of downstream pharmacodynamic effects included evaluation of immune activation markers on peripheral blood cells by flow cytometry and measurement of a panel of interferon-related cytokines in plasma.ResultsFollowing INCB086550 treatment, the ex vivo stimulation of whole blood from patients showed a dose-related reduction of up to 85% in free PD-L1 on cells after 2 hours and increases as high as 3-fold of interleukin-2 secretion after 6 hours. Increases in the proliferation of circulating T cells, as measured by Ki-67, were dose-related and as high as 2.5-fold posttreatment. Plasma concentrations of CXCL9 and CXCL10 increased following INCB086550 treatment by 1.3- and 1.4-fold, respectively. A dose-related 1.2-fold increase in the plasma concentration of soluble target (PD-L1) and a 3.4-fold increase in IFN-γ was also observed posttreatment. Other proteins related to T-cell function, including but not limited to granzyme B, granzyme H, and LAG3, also increased following drug treatment.ConclusionsThese results indicate that oral administration of INCB086550 provides dose-related pharmacodynamic T-cell activation similar to data reported for PD-(L)1 mAbs and evidence that INCB086550 is biologically active in blocking PD-1:PD-L1 interactions, leading to T-cell proliferation and activation in patients. This trial continues to evaluate the intratumoral pharmacodynamic activity, safety, and efficacy of INCB086550.Ethics ApprovalThe study was approved by institutional review boards or independent ethics committees of participating institutions.ReferencesFreeman GJ, Long AJ, Iwai Y, et al. Engagement of the PD-1 immunoinhibitory receptor by a novel B7 family member leads to negative regulation of lymphocyte activation. J Exp Med. 2000;192:1027–1034.Keir ME, Butte MJ, Freeman GJ, Sharpe AH. PD-1 and its ligands in tolerance and immunity. Annu Rev Immunol 2008;26:677–704.Tumeh PC, Harview CL, Yearley JH, et al. PD-1 blockade induces responses by inhibiting adaptive immune resistance. Nature 2014;515:568–571.Herbst RS, Soria JC, Kowanetz, M, et al.. Predictive correlates of response to the anti-PD-L1 antibody MPDL3280A in cancer patients. Nature. 2014;515:563–567.

Peripheral Blood T Cells Generated After Allogeneic Bone Marrow Transplantation: Lower Levels of Bcl-2 Protein and Enhanced Sensitivity to Spontaneous and CD95-Mediated Apoptosis In Vitro. Abrogation of the Apoptotic Phenotype Coincides With the Recovery of Normal Naive/Primed T-Cell Profiles

Blood ◽  
1999 ◽  
Vol 94 (5) ◽  
pp. 1803-1813 ◽  
Author(s):  
Nadia Chafika Hebib ◽  
Olivier Déas ◽  
Matthieu Rouleau ◽  
Antoine Durrbach ◽  
Bernard Charpentier ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Allogeneic Bone Marrow Transplantation ◽  
Allogeneic Bone ◽  
Bax Protein

T-cell reconstitution after bone marrow transplant (BMT) is characterized, for at least 1 year, by the expansion of populations of T cells with a primed/memory phenotype and by reverse CD4/CD8 proportions. T lymphocytes from 26 BMT patients (mostly adults) were obtained at various times after transplantation (from 45 to ≥730 days) and were tested for susceptibility to spontaneous apoptosis and anti-Fas triggered apoptosis in vitro. Substantial proportions of CD4+ and CD8+ cells generated during the first year after transplantation, but not by day 730, exhibited in these assays decreased mitochondrial membrane potential (▵Ψm) and apoptotic DNA fragmentation. The apoptotic phenotype tended to disappear late in the follow-up period, when substantial absolute numbers of naive (CD45RA+/CD62-L+) T cells had repopulated the peripheral blood compartment of the BMT patients. The rate of spontaneous cell death in vitro was significantly correlated with lower levels of ex vivo Bcl-2 protein, as assessed by cytofluorometry and Western blot analysis. In contrast, the levels of Bax protein remained unchanged, resulting in dysregulated Bcl-2/Bax ratios. Cell death primarily concerned the expanded CD8+/CD45R0+ subpopulation, although CD45R0− subpopulations were also involved, albeit to a lesser extent. These results show that the T-cell regeneration/expansion occurring after BMT is accompanied by decreased levels of Bcl-2 and susceptibility to apoptosis.

High Frequency CD4+CD25+ Treg Cells in Nasopharyngeal Carcinoma Is Associated with Suppression of CD8 T Cell Mediated Response to Latency II EBV Antigens.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3113-3113
Author(s):  
Frederick E. Chen ◽  
Wensheng Wen ◽  
Guangwu Huang ◽  
Paul Travers ◽  
I. Anthony Dodi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Regulatory Cells ◽  
Cell Responses ◽  
Cd25 Expression ◽  
Antigen Presenting

Abstract Nasopharyngeal Carcinoma (NPC) is associated with latent Epstein Barr Virus (EBV) infection and expression of EBV latent antigen LMP2. Because of the possibility of targeting viral antigens, there is interest in developing EBV-LMP2-specific Cytotoxic T lymphocyte (CTL) immunotherapy for NPC. However, evidence suggests that CD8+ T cell responses to EBV latency II antigens are rarely detectable in these patients. Regulatory T cells have been shown to inhibit stimulation of CD8+ T cells by Antigen Presenting Cells (APC) in vitro, and may play an important role in immune tolerance to tumours. Thirteen newly diagnosed untreated HLA A2 NPC patients were investigated for CTL responses to EBV latency II antigens by flow cytometry using HLA A2 restricted tetramers specific for LMP2a derived peptides (CLG, LTA). No LMP2-specific CD8+ T cells were detected amongst peripheral blood CD8+ T cells either ex vivo or in vitro following short stimulation in ELIspot assays, although strong responses to CMV and flu peptides and PHA were elicited. To investigate the antigen presenting capability of professional APC in NPC, dendritic cells (DC) were generated from ex vivo peripheral blood monocytes and shown to express a stimulatory mature phenotype with expression of CD83 and markers of costimulation CD80 and CD86. Despite this, mature DC pulsed with LMP2 derived peptides failed to stimulate and expand autologous LMP2-specific CTL, suggesting either absence or tolerance of LMP2-specific CTL. CD4+CD25+ regulatory cells have been implicated in peripheral tolerance and inhibition of antigen-specific T cell responses, and analysis of ex vivo peripheral blood T cells from NPC patients showed increased CD25 expression constituting a mean of 22.23 % of total CD4+ T cells compared to normal control mean of 5.35% (student t-test p<0.001). CD25 was not expressed by non-CD4+ T cells including CD8+ and NK cells, indicating that CD25 expression was unlikely to have represented activation. The findings suggest that CD4+CD25+ regulatory cells may play an important role in inhibiting antigen-specific anti-tumour responses in patients with established disease.

627 The DLL3-targeted half-life extended bispecific T cell engager (HLE BiTE®) immune-oncology therapy AMG 757 has potent antitumor activity in neuroendocrine cancer

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A663-A663
Author(s):  
Keegan Cooke ◽  
Juan Estrada ◽  
Jinghui Zhan ◽  
Jonathan Werner ◽  
Fei Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Mouse Models ◽  
T Cell Activation ◽  
Phase 1 ◽  
Phase 1 Study ◽  
Human T Cells

BackgroundNeuroendocrine tumors (NET), including small cell lung cancer (SCLC), have poor prognosis and limited therapeutic options. AMG 757 is an HLE BiTE® immune therapy designed to redirect T cell cytotoxicity to NET cells by binding to Delta-like ligand 3 (DLL3) expressed on the tumor cell surface and CD3 on T cells.MethodsWe evaluated activity of AMG 757 in NET cells in vitro and in mouse models of neuroendocrine cancer in vivo. In vitro, co-cultures of NET cells and human T cells were treated with AMG 757 in a concentration range and T cell activation, cytokine production, and tumor cell killing were assessed. In vivo, AMG 757 antitumor efficacy was evaluated in xenograft NET and in orthotopic models designed to mimic primary and metastatic SCLC lesions. NSG mice bearing established NET were administered human T cells and then treated once weekly with AMG 757 or control HLE BiTE molecule; tumor growth inhibition was assessed. Pharmacodynamic effects of AMG 757 in tumors were also evaluated in SCLC models following a single administration of human T cells and AMG 757 or control HLE BiTE molecule.ResultsAMG 757 induced T cell activation, cytokine production, and potent T cell redirected killing of DLL3-expressing SCLC, neuroendocrine prostate cancer, and other DLL3-expressing NET cell lines in vitro. AMG 757-mediated redirected lysis was specific for DLL3-expressing cells. In patient-derived xenograft and orthotopic models of SCLC, single-dose AMG 757 effectively engaged human T cells administered systemically, leading to a significant increase in the number of human CD4+ and CD8+ T cells in primary and metastatic tumor lesions. Weekly administration of AMG 757 induced significant tumor growth inhibition of SCLC (figure 1) and other NET, including complete regression of established tumors and clearance of metastatic lesions. These findings warranted evaluation of AMG 757 (NCT03319940); the phase 1 study includes dose exploration (monotherapy and in combination with pembrolizumab) and dose expansion (monotherapy) in patients with SCLC (figure 2). A study of AMG 757 in patients with neuroendocrine prostate cancer is under development based on emerging data from the ongoing phase 1 study.Abstract 627 Figure 1AMG 757 Significantly reduced tumor growth in orthotopic SCLC mouse modelsAbstract 627 Figure 2AMG 757 Phase 1 study designConclusionsAMG 757 engages and activates T cells to kill DLL3-expressing SCLC and other NET cells in vitro and induces significant antitumor activity against established xenograft tumors in mouse models. These preclinical data support evaluation of AMG 757 in clinical studies of patients with NET.Ethics ApprovalAll in vivo work was conducted under IACUC-approved protocol #2009-00046.

scholarly journals 764 Expansion with IL-15 increases cytotoxicity of Vγ9Vδ2 T cells and is associated with higher levels of cytotoxic molecules and T-bet

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A812-A812
Author(s):  
Pia Aehnlich ◽  
Per Thor Straten ◽  
Ana Micaela Carnaz Simoes ◽  
Signe Skadborg ◽  
Gitte Olofsson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Expansion ◽  
Ex Vivo ◽  
Adoptive Cell Therapy ◽  
Hematological Cancers ◽  
Cytotoxic Molecules ◽  
Vγ9vδ2 T Cells ◽  
T Cell Expansion

BackgroundAdoptive cell therapy (ACT) is an approved treatment option for certain hematological cancers and has also shown success for some solid cancers. Still, benefit and eligibility do not extend to all patients. ACT with Vγ9Vδ2 T cells is a promising approach to overcome this hurdle.MethodsIn this study, we explored the effect of different cytokine conditions on the expansion of Vγ9Vδ2 T cells in vitro.ResultsWe could show that Vγ9Vδ2 T cell expansion is feasible with two different cytokine conditions: (a) 1000U/ml interleukin (IL)-2 and (b) 100U/ml IL-2+100U/ml IL-15. We did not observe differences in expansion rate or Vγ9Vδ2 T cell purity between the conditions; however, IL-2/IL-15-expanded Vγ9Vδ2 T cells displayed enhanced cytotoxicity against tumor cells, also in hypoxia. While this increase in killing capacity was not reflected in phenotype, we demonstrated that IL-2/IL-15-expanded Vγ9Vδ2 T cells harbor increased amounts of perforin, granzyme B and granulysin in a resting state and release more upon activation. IL-2/IL-15-expanded Vγ9Vδ2 T cells also showed higher levels of transcription factor T-bet, which could indicate that T-bet and cytotoxic molecule levels confer the increased cytotoxicity.ConclusionsThese results advocate the inclusion of IL-15 into ex vivo Vγ9Vδ2 T cell expansion protocols in future clinical studies.

scholarly journals Targeting human Acyl-CoA:cholesterol acyltransferase as a dual viral and T cell metabolic checkpoint

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nathalie M. Schmidt ◽  
Peter A. C. Wing ◽  
Mariana O. Diniz ◽  
Laura J. Pallett ◽  
Leo Swadling ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Human Liver ◽  
Lipid Droplets ◽  
Ex Vivo ◽  
Functional Cure ◽  
Carcinogenic Activity ◽  
Attractive Therapeutic Target ◽  
Tcr Signalling

AbstractDetermining divergent metabolic requirements of T cells, and the viruses and tumours they fail to combat, could provide new therapeutic checkpoints. Inhibition of acyl-CoA:cholesterol acyltransferase (ACAT) has direct anti-carcinogenic activity. Here, we show that ACAT inhibition has antiviral activity against hepatitis B (HBV), as well as boosting protective anti-HBV and anti-hepatocellular carcinoma (HCC) T cells. ACAT inhibition reduces CD8+ T cell neutral lipid droplets and promotes lipid microdomains, enhancing TCR signalling and TCR-independent bioenergetics. Dysfunctional HBV- and HCC-specific T cells are rescued by ACAT inhibitors directly ex vivo from human liver and tumour tissue respectively, including tissue-resident responses. ACAT inhibition enhances in vitro responsiveness of HBV-specific CD8+ T cells to PD-1 blockade and increases the functional avidity of TCR-gene-modified T cells. Finally, ACAT regulates HBV particle genesis in vitro, with inhibitors reducing both virions and subviral particles. Thus, ACAT inhibition provides a paradigm of a metabolic checkpoint able to constrain tumours and viruses but rescue exhausted T cells, rendering it an attractive therapeutic target for the functional cure of HBV and HBV-related HCC.

scholarly journals IMMU-31. QUANTITATIVE EVALUATION OF ROUTES OF ADMINISTRATION OF IMMUNOTHERAPEUTIC T CELLS TO ORTHOTOPIC GLIOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii111-ii111
Author(s):  
Lan Hoang-Minh ◽  
Angelie Rivera-Rodriguez ◽  
Fernanda Pohl-Guimarães ◽  
Seth Currlin ◽  
Christina Von Roemeling ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Ex Vivo ◽  
Adoptive T Cell Therapy ◽  
Whole Body ◽  
T Cell Therapy ◽  
Clinical Responses

Abstract SIGNIFICANCE Adoptive T cell therapy (ACT) has emerged as the most effective treatment against advanced malignant melanoma, eliciting remarkable objective clinical responses in up to 75% of patients with refractory metastatic disease, including within the central nervous system. Immunologic surrogate endpoints correlating with treatment outcome have been identified in these patients, with clinical responses being dependent on the migration of transferred T cells to sites of tumor growth. OBJECTIVE We investigated the biodistribution of intravenously or intraventricularly administered T cells in a murine model of glioblastoma at whole body, organ, and cellular levels. METHODS gp100-specific T cells were isolated from the spleens of pmel DsRed transgenic C57BL/6 mice and injected intravenously or intraventricularly, after in vitro expansion and activation, in murine KR158B-Luc-gp100 glioma-bearing mice. To determine transferred T cell spatial distribution, the brain, lymph nodes, heart, lungs, spleen, liver, and kidneys of mice were processed for 3D imaging using light-sheet and multiphoton imaging. ACT T cell quantification in various organs was performed ex vivo using flow cytometry, 2D optical imaging (IVIS), and magnetic particle imaging (MPI) after ferucarbotran nanoparticle transfection of T cells. T cell biodistribution was also assessed in vivo using MPI. RESULTS Following T cell intravenous injection, the spleen, liver, and lungs accounted for more than 90% of transferred T cells; the proportion of DsRed T cells in the brains was found to be very low, hovering below 1%. In contrast, most ACT T cells persisted in the tumor-bearing brains following intraventricular injections. ACT T cells mostly concentrated at the periphery of tumor masses and in proximity to blood vessels. CONCLUSIONS The success of ACT immunotherapy for brain tumors requires optimization of delivery route, dosing regimen, and enhancement of tumor-specific lymphocyte trafficking and effector functions to achieve maximal penetration and persistence at sites of invasive tumor growth.

scholarly journals Quantitative assessment of the pool size and subset distribution of cytolytic T lymphocytes within human resting or alloactivated peripheral blood T cell populations.

1983 ◽  
Vol 158 (2) ◽  
pp. 571-585 ◽  
Author(s):  
A Moretta ◽  
G Pantaleo ◽  
L Moretta ◽  
M C Mingari ◽  
J C Cerottini
Keyword(s):  
Monoclonal Antibody ◽  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Peripheral Blood ◽  
Great Majority ◽  
T Cell Subsets ◽  
Cytolytic T Lymphocytes ◽  
Subset Distribution

In order to directly assess the distribution of cytolytic T lymphocytes (CTL) and their precursors (CTL-P) in the two major subsets of human T cells, we have used limiting dilution microculture systems to determine their frequencies. The two subsets were defined according to their reactivity (or lack thereof) with B9.4 monoclonal antibody (the specificity of which is similar, if not identical, to that of Leu 2b monoclonal antibody). Both B9+ and B9- cells obtained by sorting peripheral blood resting T cells using the fluorescence-activated cell sorter (FACS) were assayed for total CTL-P frequencies in a microculture system that allows clonal growth of every T cell. As assessed by a lectin-dependent assay, approximately 30% of peripheral blood T cells were CTP-P. In the B9+ subset (which represents 20-30% of all T cells), the CTL-P frequency was close to 100%, whereas the B9- subset had a 25-fold lower CTL-P frequency. It is thus evident that 90% and 10% of the total CTL-P in peripheral blood are confined to the B9+ or B9- T cell subsets, respectively. Analysis of the subset distribution of CTL-P directed against a given set of alloantigens confirmed these findings. CTL-P frequencies were also determined in B9+ and B9- subsets derived from T cells that had been activated in allogenic mixed leucocyte cultures (MLC). Approximately 10% of MLC T cells were CTL-P. This frequency was increased 3.5-fold in the B9+ subset, whereas the B9- subset contained only a small, although detectable number of CTL-P. Moreover, the great majority of the (operationally defined) CTL-P in MLC T cell population were found to be directed against the stimulating alloantigens, thus indicating a dramatic increase in specific CTL-P frequencies following in vitro stimulation in bulk cultures.

scholarly journals Cytokine production in ex-vivo stimulated fresh and cryopreserved T-cells

2021 ◽  
Vol 67 (2) ◽  
pp. 95-101
Author(s):  
Monica Vuță ◽  
Ionela-Maria Cotoi ◽  
Ion Bogdan Mănescu ◽  
Doina Ramona Manu ◽  
Minodora Dobreanu
Keyword(s):  
T Cells ◽  
Peripheral Blood ◽  
Cd4 T Cells ◽  
Mononuclear Cells ◽  
Cytokine Production ◽  
Ex Vivo ◽  
Gradient Centrifugation ◽  
Intracellular Cytokine Staining ◽  
Interleukin 2 ◽  
Middle Aged

Abstract Objective: In vitro cytokine production by peripheral blood mononuclear cells (PBMCs) is an important and reliable measure of immunocompetence. PBMC can be stimulated directly after isolation or frozen for later use. However, cryopreservation may affect cell recovery, viability and functionality. This study aims to investigate cytokine synthesis in ex-vivo stimulated fresh and cryopreserved CD4+ and CD4- T cells. Methods: PBMCs were obtained by Ficoll gradient centrifugation from heparinized peripheral blood of 6 middle-aged clinically healthy subjects. Half of these cells (labeled “Fresh”) was further processed and the other half (labeled “Cryo”) was cryopreserved at -140°C for up to 3 months. Fresh-PBMCs were activated with Phorbol-Myristate-Acetate/Ionomycin/Monensin for 5 hours immediately after isolation while Cryo-PBMCs were identically activated after thawing and cell resting. Activated cells were fixed, permeabilized and intracellular cytokine staining was performed using Phycoerythrin (PE)-conjugated antibodies for Interleukin-2 (IL-2), Tumor Necrosis Factor-alpha (TNF-a), and Interferon-gamma (IFN-g). All samples were analyzed within 24 hours by flow cytometry. Results: Both Fresh and Cryo CD3+CD4+/CD3+CD4- sub-populations partially produced each of the three cytokines. A higher percentage of CD4+ T cells produced IL-2 and TNF-a and a greater percentage of CD4- T cells were found to produce IFN-g. A significantly higher percentage of Cryo-lymphocytes was shown to produce TNF-a in both CD3+CD4+ (31.4% vs 24.9%, p=0.031) and CD3+CD4- (22.7% vs 17.9%, p=0.031) subpopulations. No notable difference was found for IL-2 and IFN-g production between Fresh and Cryo T cells. Conclusion: Cryopreservation for up to 3 months significantly increases TNF-a production of T-cells in clinically healthy middle-aged subjects.

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